Process of protecting exposed filters or other confined liquid bodies from freezing.



Patented My 29, I902. L. K. DAVIS.

PROCESS OF PROTECTING EXPOSED FILTERS OR OTHER OONFINEO LIOUIO BODIESFROM FREEZING.

(Application, filed Mar. 5, 1900. Renewed. Jan. 14, 1902') (N0 Model.)

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UNITED STATES PATENT OFFICE.

LEWIS K. DAVIS, OF INDIANAPOLIS, INDIANA.

PROCESSOF PROTECTING EXPOSED FILTERS OR OTHER CONFINED LIQUID BODIESFROM FREEZING.

SPECIFICATION forming part Of LettersPatent No. 705,740, dated. July 29,1902. Application filed March 5, 1900. Renewed January 14:, 1902. SerialNo. 89,730. (No specimens.)

To all whom it may concern.- 7

Be it known that I, LEWIS K. DAVIS, postoffice address and residenceIndianapolis, Indiana, have invented certain new and useful Improvementsin Processes of Protecting Exposed Filters or other Confined LiquidBodies from Freezing, of which the following is a descriptionillustrated bydrawings of one type of the invention.

I will describe my invention in relation to a particular type offilter-beds to which it is peculiarly fitted, and from this the natureof the invention as applied under other conditions should be readilyapprehended. Suppose we have a filter-bed or a number of them each anacre in extent and containing the filtering layers of sand, 820.,covered by a foot or two of water. It is essential to keep such a bodyof water from freez'ing'not only because of the mechanical troubles thatarise I from the ice, but also because the ice forms a substantiallyair-tight cover to the Water, and it is highly desirable that freedom toabsorb oxygen from the air should not be inter-- rupted. It is neitherpractical nor desirable to directly protect the whole surface of thewater by lattice-work orgridwork of heatingpipes. I have discovered thatit is sufficient if ice is prevented from forming at the mar-- gin ofthe body of Water, because, as is well known, crystallization does nottake place readily in a body of liquid unless there are solid particlesfrom which the crystals may Applying this principle to the practicalproblem of preventing the freezing of such a body of Water I ,havediscovered that if heat be supplied just beneath the surface and aroundthe margin, preferably the entire margin, of the body of water the factthat the ice crystals are thus prevented from forming on the Walls ofthe filter or even if they form are prevented from crossing the lineofheatedwater made by the steam-pipe or other heating agency used initself indirectly prevents the formation of ice in the central portionsof the surface of the water, because there are no solid points therepresent to facilitate the crystallization. In addition to this indirecteffect the heating of the marginal portions of the surfaceof the Watermay and I believe does cause a circulation along the surface of thewater from the margins toward the middle, though I do not pretend toaccount for this in the face of the fact that water at a temperaturebetween 32 and 40 Fahrenheit, if pure, is heavier than water at thefreezing-point, 32. It is possible, therefore, that the circulation maytake place by the falling down of the slightly-warm water and its flowalong the surface ofthe sand or other filtering substance and toward thecenter of the body of Water and by a countercurrent at the surface.

In the drawings, Figure 1 is a small-scale plan View of a portion offour such filter-beds as I have described, oneof them being marked b.One or more steam-pipes 19 extend around the entire margin. Fig. 2 is adetail partial plan view on a larger scale, and Fig. 3 is a partialvertical sectional view. I

The steam-pipe in the system illustrate must be open at some point, soas to allow the condensed steam to run out, no return or exhaust pipebeingshown. This pipep is placed only a few inches beneath the surfaceand preferably only an inch or two from the wall 20 of the filter. It issupplied with steam and is also supported by the pipes r, provided withinlet-valves s, as shown. The pipes r are supplied from mains in, whichare preferably heavily protected by asbestos or other nonconductingmaterial, as shown.

WVhen the cold weather is over, the pipes 19 may be disconnectedfrom thepipes r and entirely removed from thefilters. Owing, however, to theirbeing arranged annularly--that is to say, only around the edge or marginof the water-they do not interfere with the removal or the washing ofthe sand bed or filter f.

As this application refers exclusively to my improvement in the art, IWant it to be clearly understood that I seek protection for myimprovement in the apparatus or article of manufacture in another patentapplication.

Having now fully set forth and explained one form of my invention, Iclaim as the novel features that characterize it the following:

1. The improvement in the art of preventing exposed filters and otherconfined liquid bodies from freezing, which consists in supplying heatbeneath the surface at or near the vertical confining-walls and causinga circulation of the relatively heated water from such points, wherebythe marginal portions of the exposed filters and other confined liquidbodliquid are prevented from freezing, and the ies from freezing, whichconsists in supplying more central open surface protected thereby. heatin an annular line beneath the surface.

2. Theiinprovementin the art ofpreventing of the liquid andsubstantially at its margin, 15 5 exposed filters and other confinedliquid bodfor the purposes set forth.

ies from freezing, which consists in heating Signed this 15th day ofJanuary, 1900, at

marginal portions of the liquid and causing J New York, N. Y. acirculation to take place from such marginal portions and toward thecenter, substantially Witnesses: 10 as and forthe purposes set forth;

3. Theimprovelnentin the artofpreventing LEWIS K. DAVIS.

EDWARD A. FREsHMAN, HAROLD BINNEY.

